Lighting device and projector
View Patent ↗A lighting device includes: a light source unit which supplies coherent light; a polarized light splitting unit which reflects first polarized light having first oscillation direction and transmits second polarized light having second oscillation direction substantially orthogonal to the first oscillation direction to split the first polarized light from the second polarized light; a reflection unit which reflects light advancing in a direction other than the lighting direction from the polarized light splitting unit; a partial reflection unit disposed between the polarized light splitting unit and the reflection unit to transmit a part of entering light and reflect the other part of the entering light; and a wavelength plate disposed between the polarized light splitting unit and the partial reflection unit to vary polarization condition of entering light.
1. A lighting device, comprising:
a light source unit which supplies coherent light;
a polarized light splitting unit which reflects first polarized light having first oscillation direction and transmits second polarized light having second oscillation direction substantially orthogonal to the first oscillation direction to split the first polarized light from the second polarized light;
a reflection unit which reflects light advancing in a direction other than the lighting direction from the polarized light splitting unit;
a partial reflection unit disposed between the polarized light slitting unit and the reflection unit to transmit a part of entering light and reflect the other part of the entering light; and
a wavelength plate disposed between the polarized light splitting unit and the partial reflection unit to vary polarization condition of entering light.
2. The lighting device according to claim 1 , wherein the partial reflection unit and the reflection unit are disposed with a distance corresponding to half of a coherent length of the coherent light or longer between the partial reflection unit and the reflection unit.
3. The lighting device according to claim 1 , wherein the polarized light splitting unit and the reflection unit are disposed on a common optical axis.
4. The lighting device according to claim 1 , further including a light guide unit through which light propagates between the partial reflection unit and the reflection unit.
5. The lighting device according to claim 4 , wherein the light guide unit has a rod integrator.
6. The lighting device according to claim 1 , further including a variable refractive index element which transmits light propagating between the partial reflection unit and the reflection unit and varies refractive index.
7. The lighting device according to claim 1 , further including the plural partial reflection units.
8. The lighting device according to claim 1 , wherein the reflection unit has a prism unit which reflects light with total reflection.
9. A projector, comprising:
the lighting device according to claim 1 ; and
a spatial light modulating unit which modulates light emitted from the lighting device according to an image signal.